Which statement is true when driving in a roundabout?

When navigating a roundabout, the key rule is that the vehicle already within the roundabout holds the right of way. This is designed to enhance safety and streamline traffic flow by allowing vehicles that are already in the roundabout to proceed without interruption. Drivers approaching the roundabout must yield to any traffic that is circulating within it before entering, ensuring a smooth transition and minimizing stop-and-go traffic, which can contribute to accidents.

In this context, the other statements do not align with the standard rules of right of way in roundabouts. For instance, entering drivers do not have priority, and therefore must yield, counter to what some might assume about traffic patterns. Larger vehicles may have certain considerations regarding space and navigation, but that does not inherently grant them a blanket right of way. Speed in roundabouts is also typically lower than that in other types of intersections, aligning with safety practices rather than encouraging faster speeds. Thus, the principle that the vehicle in the roundabout has the right of way is critical for safe and efficient traffic movement.